1. Field of the Invention
The present invention relates generally to blow molding devices and more particularly to a device for controlling rotation of a blow needle.
2. Related Art
When blow molding products, a blow cylinder body is used to position a needle to create the proper blow hole through which to blow air into the product. A clean blow hole is essential to blow an attractive, functional product. Proper positioning of the needle relative to the parison is crucial for purposes of creating a clean blow hole.
When working with a nonconcentric or nonuniform tip, such as an angled tip, positioning becomes particularly challenging. Blow needles can have angled tips where the angle can vary from about 10° to about 80°. The position of the tip, which determines the direction in which air enters the blow mold, can affect the appearance and quality of a blow molded article. Devices currently available in the art require a significant amount of guesswork when determining the ideal position for a blow needle. First, a user must make an educated guess as to where to locate the needle. Then a dowel pin is positioned, for example, at the underside of the needle piston or on the back side of the piston to prevent rotation of the piston, thus preventing rotation of the needle. If the needle is not in the optimal location, the dowel pin has to be removed, then the needle removed, repositioned, and the entire procedure started again.
This method often results in a failure to obtain the desired results, and therefore is highly inefficient. Not only is adjustment time-consuming and frustrating, but the process can require expensive reworking when an error is made.
Thus, there is a need in the art for a device that allows for easy positioning and repositioning of the blow needle during the blow molding process.